code for generating onboarding signature

lib/razorpay/utility.rb

@@ -26,6 +26,11 @@ def self.verify_webhook_signature(body, signature, secret)
       verify_signature(body, signature, secret)
     end
 
+    def self.generate_onboarding_signature(body, secret)
+      json_data = body.to_json
+      encrypt(json_data, secret);
+    end
+
     class << self
       private
 
@@ -52,6 +57,25 @@ def secure_compare(a, b)
 
         r.zero?
       end
+
+      def encrypt(data, secret)
+        iv = secret[0, 12]
+        key = secret[0, 16]
+
+        cipher = OpenSSL::Cipher.new('aes-128-gcm')
+        cipher.encrypt
+        cipher.key = key
+        cipher.iv = iv
+
+        cipher.auth_data = ""
+
+        encrypted = cipher.update(data) + cipher.final
+
+        tag = cipher.auth_tag
+        combined_encrypted_data = encrypted + tag
+
+        encrypted_data_hex = combined_encrypted_data.unpack1("H*")
+      end
     end
   end
 end

test/razorpay/test_utility.rb

@@ -1,4 +1,5 @@
 require 'test_helper'
+require 'json'
 
 module Razorpay
   # Tests for Razorpay::Utility
@@ -80,5 +81,38 @@ def test_webhook_signature_verification
         Razorpay::Utility.verify_webhook_signature(webhook_body, signature, secret)
       end
     end
+
+    def test_generate_onboarding_signature
+      secret = "EnLs21M47BllR3X8PSFtjtbd"
+      timestamp = Time.now.to_i
+      body = {
+        submerchant_id: 'NSgKfYIR2f9v2y',
+        timestamp: timestamp
+      }
+      encryptedData = Razorpay::Utility.generate_onboarding_signature(body, secret)
+      json_data = decrypt(encryptedData, secret)
+      body = JSON.parse(json_data)
+      assert_equal 'NSgKfYIR2f9v2y', body['submerchant_id'], 'Submerchant IDs do not match'
+      assert_equal timestamp, body['timestamp'], 'Timestamps do not match'
+    end
+
+    def decrypt(data, secret)
+      combined_encrypted_data = [data].pack("H*")
+
+      iv = secret[0, 12]
+      key = secret[0, 16]
+      tag = combined_encrypted_data[-16..]
+
+      encrypted_data = combined_encrypted_data[0...-16]
+
+      cipher = OpenSSL::Cipher.new('aes-128-gcm')
+      cipher.decrypt
+      cipher.key = key
+      cipher.iv = iv
+      cipher.auth_tag = tag
+      cipher.auth_data = ""
+
+      cipher.update(encrypted_data) + cipher.final
+    end
   end
 end